1 
2 #if !defined(BOOST_PP_IS_ITERATING)
3 
4 ///// header body
5 
6 //-----------------------------------------------------------------------------
7 // boost variant/detail/substitute.hpp header file
8 // See http://www.boost.org for updates, documentation, and revision history.
9 //-----------------------------------------------------------------------------
10 //
11 // Copyright (c) 2003
12 // Eric Friedman
13 //
14 // Distributed under the Boost Software License, Version 1.0. (See
15 // accompanying file LICENSE_1_0.txt or copy at
16 // http://www.boost.org/LICENSE_1_0.txt)
17 
18 #ifndef BOOST_VARIANT_DETAIL_SUBSTITUTE_HPP
19 #define BOOST_VARIANT_DETAIL_SUBSTITUTE_HPP
20 
21 #include <boost/mpl/aux_/config/ctps.hpp>
22 
23 #include <boost/variant/detail/substitute_fwd.hpp>
24 #include <boost/variant/variant_fwd.hpp> // for BOOST_VARIANT_DO_NOT_USE_VARIADIC_TEMPLATES
25 #include <boost/mpl/aux_/lambda_arity_param.hpp>
26 #include <boost/mpl/aux_/preprocessor/params.hpp>
27 #include <boost/mpl/aux_/preprocessor/repeat.hpp>
28 #include <boost/mpl/int_fwd.hpp>
29 #include <boost/mpl/limits/arity.hpp>
30 #include <boost/preprocessor/cat.hpp>
31 #include <boost/preprocessor/empty.hpp>
32 #include <boost/preprocessor/arithmetic/inc.hpp>
33 #include <boost/preprocessor/iterate.hpp>
34 
35 namespace boost {
36 namespace detail { namespace variant {
37 
38 #if !defined(BOOST_VARIANT_DETAIL_NO_SUBSTITUTE)
39 
40 ///////////////////////////////////////////////////////////////////////////////
41 // (detail) metafunction substitute
42 //
43 // Substitutes one type for another in the given type expression.
44 //
45 
46 //
47 // primary template
48 //
49 template <
50       typename T, typename Dest, typename Source
51       BOOST_MPL_AUX_LAMBDA_ARITY_PARAM(
52           typename Arity /* = ... (see substitute_fwd.hpp) */
53         )
54     >
55 struct substitute
56 {
57     typedef T type;
58 };
59 
60 //
61 // tag substitution specializations
62 //
63 
64 #define BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL_SUBSTITUTE_TAG(CV_) \
65     template <typename Dest, typename Source> \
66     struct substitute< \
67           CV_ Source \
68         , Dest \
69         , Source \
70           BOOST_MPL_AUX_LAMBDA_ARITY_PARAM(mpl::int_<-1>) \
71         > \
72     { \
73         typedef CV_ Dest type; \
74     }; \
75     /**/
76 
77 BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL_SUBSTITUTE_TAG( BOOST_PP_EMPTY() )
78 BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL_SUBSTITUTE_TAG(const)
79 BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL_SUBSTITUTE_TAG(volatile)
80 BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL_SUBSTITUTE_TAG(const volatile)
81 
82 #undef BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL_SUBSTITUTE_TAG
83 
84 //
85 // pointer specializations
86 //
87 #define BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL_HANDLE_POINTER(CV_) \
88     template <typename T, typename Dest, typename Source> \
89     struct substitute< \
90           T * CV_ \
91         , Dest \
92         , Source \
93           BOOST_MPL_AUX_LAMBDA_ARITY_PARAM(mpl::int_<-1>) \
94         > \
95     { \
96         typedef typename substitute< \
97               T, Dest, Source \
98             >::type * CV_ type; \
99     }; \
100     /**/
101 
102 BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL_HANDLE_POINTER( BOOST_PP_EMPTY() )
103 BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL_HANDLE_POINTER(const)
104 BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL_HANDLE_POINTER(volatile)
105 BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL_HANDLE_POINTER(const volatile)
106 
107 #undef BOOST_VARIANT_AUX_ENABLE_RECURSIVE_IMPL_HANDLE_POINTER
108 
109 //
110 // reference specializations
111 //
112 template <typename T, typename Dest, typename Source>
113 struct substitute<
114       T&
115     , Dest
116     , Source
117       BOOST_MPL_AUX_LAMBDA_ARITY_PARAM(mpl::int_<-1>)
118     >
119 {
120     typedef typename substitute<
121           T, Dest, Source
122         >::type & type;
123 };
124 
125 //
126 // template expression (i.e., F<...>) specializations
127 //
128 
129 #if !defined(BOOST_VARIANT_DO_NOT_USE_VARIADIC_TEMPLATES)
130 template <
131       template <typename...> class F
132     , typename... Ts
133     , typename Dest
134     , typename Source
135       BOOST_MPL_AUX_LAMBDA_ARITY_PARAM(typename Arity)
136     >
137 struct substitute<
138       F<Ts...>
139     , Dest
140     , Source
141       BOOST_MPL_AUX_LAMBDA_ARITY_PARAM(Arity)
142     >
143 {
144     typedef F<typename substitute<
145           Ts, Dest, Source
146         >::type...> type;
147 };
148 #endif // !defined(BOOST_VARIANT_DO_NOT_USE_VARIADIC_TEMPLATES)
149 
150 #define BOOST_VARIANT_AUX_SUBSTITUTE_TYPEDEF_IMPL(N) \
151     typedef typename substitute< \
152           BOOST_PP_CAT(U,N), Dest, Source \
153         >::type BOOST_PP_CAT(u,N); \
154     /**/
155 
156 #define BOOST_VARIANT_AUX_SUBSTITUTE_TYPEDEF(z, N, _) \
157     BOOST_VARIANT_AUX_SUBSTITUTE_TYPEDEF_IMPL( BOOST_PP_INC(N) ) \
158     /**/
159 
160 #define BOOST_PP_ITERATION_LIMITS (0,BOOST_MPL_LIMIT_METAFUNCTION_ARITY)
161 #define BOOST_PP_FILENAME_1 <boost/variant/detail/substitute.hpp>
162 #include BOOST_PP_ITERATE()
163 
164 #undef BOOST_VARIANT_AUX_SUBSTITUTE_TYPEDEF_IMPL
165 #undef BOOST_VARIANT_AUX_SUBSTITUTE_TYPEDEF
166 
167 #endif // !defined(BOOST_VARIANT_DETAIL_NO_SUBSTITUTE)
168 
169 }} // namespace detail::variant
170 } // namespace boost
171 
172 #endif // BOOST_VARIANT_DETAIL_SUBSTITUTE_HPP
173 
174 ///// iteration, depth == 1
175 
176 #elif BOOST_PP_ITERATION_DEPTH() == 1
177 #define i BOOST_PP_FRAME_ITERATION(1)
178 
179 #if i > 0
180 
181 //
182 // template specializations
183 //
184 template <
185       template < BOOST_MPL_PP_PARAMS(i,typename P) > class T
186     , BOOST_MPL_PP_PARAMS(i,typename U)
187     , typename Dest
188     , typename Source
189     >
190 struct substitute<
191       T< BOOST_MPL_PP_PARAMS(i,U) >
192     , Dest
193     , Source
194       BOOST_MPL_AUX_LAMBDA_ARITY_PARAM(mpl::int_<( i )>)
195     >
196 {
197 private:
198     BOOST_MPL_PP_REPEAT(i, BOOST_VARIANT_AUX_SUBSTITUTE_TYPEDEF, _)
199 
200 public:
201     typedef T< BOOST_MPL_PP_PARAMS(i,u) > type;
202 };
203 
204 //
205 // function specializations
206 //
207 template <
208       typename R
209     , BOOST_MPL_PP_PARAMS(i,typename U)
210     , typename Dest
211     , typename Source
212     >
213 struct substitute<
214       R (*)( BOOST_MPL_PP_PARAMS(i,U) )
215     , Dest
216     , Source
217       BOOST_MPL_AUX_LAMBDA_ARITY_PARAM(mpl::int_<-1>)
218     >
219 {
220 private:
221     typedef typename substitute< R, Dest, Source >::type r;
222     BOOST_MPL_PP_REPEAT(i, BOOST_VARIANT_AUX_SUBSTITUTE_TYPEDEF, _)
223 
224 public:
225     typedef r (*type)( BOOST_MPL_PP_PARAMS(i,u) );
226 };
227 
228 #elif i == 0
229 
230 //
231 // zero-arg function specialization
232 //
233 template <
234       typename R, typename Dest, typename Source
235     >
236 struct substitute<
237       R (*)( void )
238     , Dest
239     , Source
240       BOOST_MPL_AUX_LAMBDA_ARITY_PARAM(mpl::int_<-1>)
241     >
242 {
243 private:
244     typedef typename substitute< R, Dest, Source >::type r;
245 
246 public:
247     typedef r (*type)( void );
248 };
249 
250 #endif // i
251 
252 #undef i
253 #endif // BOOST_PP_IS_ITERATING
254